1. Field of the Invention
The present invention relates to a device for disinfecting of gases and/or liquids.
2. Description of the Related Art
An already known method is to utilize ultraviolet (UV) radiation for treatment, in particular disinfecting or respectively sterilizing water, air or surfaces. Drinking water treatment by means of UV-radiation has hitherto been relatively common, whereby the germination index in the water can be greatly reduced reliably and dependent upon the dose. UV-radiation inactivates micro-organisms such as pathogens, in particular bacteria or viruses.
UV-disinfection offers a series of advantages compared to conventional disinfection, based on chemical processes. UV-disinfection is a simple and rapidly effective process whereby disinfection occurs immediately during the exposure of the medium. Another great advantage of UV-disinfection is that neither taste, odor, nor pH-value of the disinfected medium is influenced. This represents a substantial difference from the chemical treatment of drinking or process water. In contrast to the chemical disinfection process additional disinfection agents are not required. Maintenance and monitoring of dosing equipment are not required and special safety regulations are also not necessary. An additional advantage is that it is environmentally friendly since no secondary reactions due to formation of undesired compounds occur. In contrast to conventional disinfection agents no resistance due to mutation, as is often the case for example with hospital specific germs (for example antibiotic-resistance), are developed in UV-disinfection. UV-disinfection is also possible in a large scale, for example in communal drinking water processing. It is also possible in continuous operation to keep the germination index constantly low.
In UV-disinfection, mercury vapor lamps which emit radiation at a wavelength of around 254 nanometers (nm) are normally utilized. Shorter wavelengths below 200 nm are so short-wave that they are absorbed by molecular oxygen, whereby the molecular oxygen is split into free oxygen radicals and can further react with additional oxygen molecules to create ozone. Short wave UV-radiation of this type is also utilized to produce ultrapure water.
Numerous suggestions for UV-disinfection are known from the current state of the art. Some of these are discussed hereafter. For example, DE 38 37 905 A1 describes a method and a device for the treatment, in particular disinfection of liquids and/or gases by means of UV-light sources, whereby the device is a tubular reaction chamber for the medium which is to be treated and comprises at least two UV-light sources, whereby light sources differing from each other are provided which respectively emit different wave lengths and which jointly can be operated in selectable combinations together or, alternatively, separately. The UV-light sources are located either in the reaction chamber and are immersed into the medium and are surrounded by same, or are positioned outside and at a distance from the reaction chamber.
DE 38 24 647 A1 relates to a device to radiate mediums by means of UV-light, consisting of a tubular body of UV-permeable material through which medium flows, and at least two UV-light sources with reflectors mounted externally axially parallel whereby the light sources represent UV flat emitters having an elongated, flat oval cross section with a broadside and a narrow side. The main axis of the UV-light sources are always directed to the center point of the tubular body cross section. The UV-light sources are arranged ring-shaped and axially parallel around the tubular body through which the medium flows. According to one embodiment, the flat emitters fit against the tubular body with the narrow side facing the tubular body.
U.S. Pat. No. 5,133,932 discloses a device to sterilize blood and other liquids of biological origin, whereby a container which is transparent regarding UV-radiation is rotated with the liquid to be sterilized and is simultaneously radiated from the outside with UV-radiation. The container may possess a wave-like surface. The UV-light sources are however located outside the rotatable container.
DE 196 17 467 A1 furthermore concerns a device for disinfecting of water by means of UV-C-rays, whereby the water flows through a quartz glass tube and whereby one or several UV radiators are positioned around the quartz glass tube.
DE 10 2010 005 893 A1 discloses a line for the production of ultrapure water, comprising at least one inlet for the water to be purified, a purification unit, a UV-radiation unit with at least one UV-ray emitting light source which is designed for radiating the water flowing through the UV-radiation unit, as well as one outlet. The UV-radiation units, for example in the embodiment of UV-LEDs (light emitting diodes), are arranged either externally of the conduit system 14 (FIG. 6d) or are integrated into the walls of conduit system 14 (FIGS. 6a, 6b and 6c). It is particularly preferred if the UV-radiation unit protrudes at least partially into the flowing water.
WO 2009/013507 relates to a treatment device for at least partial disinfection of a fluid such as water, comprising one conduit for conveying a flow of fluid to be treated, a multitude of LEDs for the emission of UV-light into the fluid, as well as a control circuit for controlling the LEDs by means of a pulsed signal for pulsing the light source. Herein the UV-LEDs are arranged such that the fluid flows directly over a surface of each light source. The direct contact of the fluid with the UV-source/sources is intended to provide greater treatment efficiency due to the closer proximity of the light source to the fluid to be treated. Furthermore, a cooling effect provided by the UV-LEDs allows operation of the LED at highest UV-light intensity, thereby increasing fields of application and efficiency.
A problem in the direct contact of UV-light source and medium to be treated is in that the surface of the UV-light source must be resistant against the medium and must be sealed against same. Each UV-LED must be individually sealed. The cooling effect, for example that of a liquid, can no longer be utilized if the liquid itself is not cool, but is instead warm or even hot. In such a case the hot liquid causes even additional heating of the UV-LEDs and can thereby clearly limit their life span.
The described treatment systems also have the disadvantage here that no simple replacement of the UV-light source can occur, since this is in direct contact with the medium to be treated. Shutting down the entire system is therefore required, thereby reducing the efficiency of the method.
U.S. Pat. No. 7,270,748 B1 describes a water purification system for a water faucet by use of UV-radiation. Part of the water flow is equipped with a multitude of UV-LEDs which can be arranged around the transparent conduit and may be embedded in same.
U.S. Patent Application Publication No. 2003/0170151 A1 discloses a system wherein a fluid is subjected to UV-radiation. The system includes a conduit for conveying the fluid, whereby the conduit is baffled so that the fluid flow is rendered more uniform. The UV-light sources are hereby arranged in the conduit or can also be provided on the baffle unit. The UV-light sources are hereby again in direct contact with the fluid to be treated, resulting in the already described disadvantages.
U.S. Patent Application Publication No. 2010/0253207 A1 describes a flat discharge lamp of a very special design to produce UV-radiation which, in addition to other applications, can also be used to disinfect/sterilize air, water or surfaces.
Accordingly, two essentially different design concepts for UV-disinfection units are known from the current state of the art:                a) units wherein the UV-light sources are surrounded by the medium to be disinfected; and        b) units wherein the UV-light sources are arranged outside the medium to be disinfected.        
Disadvantages of known systems of type (b) are low efficiency and large space requirement. With these systems the UV-light sources are arranged outside a UV-permeable tube, through which the medium to be disinfected flows. In order to guarantee the minimum radiation necessary for radiation in the interior space which is completely filled with flowing medium, a multitude of UV-light sources must either be arranged around the tube, or the UV-radiation of fewer light sources must be distributed to a sufficient extent over an expensive reflector system which requires a comparatively large space. In order to achieve sufficient disinfection performance two criteria must be met: the radiation intensity must be sufficiently high over the entire range to be disinfected, which means that the intensity of the radiation for disinfection should not fall below a certain radiation minimum. Moreover, a distribution of radiation which is as homogeneous as possible should be present in the medium to be disinfected. Systems known from the current state of the art however, typically have the problem of poor utilization of UV light, caused by shading, multiple reflections and loss mechanisms, in particular on the reflective surfaces of the reflector system. Due to the generally undirected radiation of the UV-light sources, only a small portion of the radiation takes a direct path through the UV-permeable tube into the medium to be disinfected. The remaining portion must be directed into the tube via reflectors. Reflector materials, such as aluminum however absorb a significant portion of the UV-radiation. In the case of aluminum, this absorption is approximately 15% at a wavelength of 254 nm. This portion of UV-radiation is lost and is no longer available to disinfect.
Moreover, the known arrangements of UV-light sources and reflectors require a lot of space and are therefore suitable only to a limited extent for applications requiring a small space.
What is needed in the art is a device wherein the disadvantages of the current state of the art are avoided and which provides an effective disinfection of liquids or gases using UV-radiation while maintaining the known advantages of a UV-disinfection, whereby better utilization of the UV-radiation produced by the light sources is achieved. Moreover the inventive device is to provide high compactness in regard to its construction.